How much sleep do you need to avoid mental decline?

Everything is good in moderation, including sleep. The brains of older people were studied at Washington University in St. Louis. It turned out that cognitive impairment was not only in those who sleep less than necessary, but also in those who like to sleep longer, says "Voice of America".

“The cognitive function of the brain encompasses short-term memory, visual memory, and information processing. Cognitive ability tests are our methods of assessing various types of memory and thinking functions. For example, there are tests that ask you to name as many animal names as possible in a given period of time,” says Brendan Lucy, a researcher at St. Louis University.

The study lasted about 4,5 years. The average age of participants is 75 years. Unlike the previous Research, where the participants were simply asked about the time of sleep, in Lucy's study, each phase of sleep was recorded by an electroencephalogram.

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According to Brendan Lucy, the study included 100 people aged 65 and older. They were followed over time to study the brain changes caused by age and Alzheimer's disease.

The study used a number of sophisticated medical tests. The researchers took pictures of the brain, studied the sleep of the participants. Participants were also given lumbar punctures to take fluid from around the brain and spinal cord. In this way, the changes that appear during the disease are measured. Alzheimer's.

During the experiment, scientists tried to answer the question “How exactly is the quality of various stages of sleep related to impaired brain function in Alzheimer's disease?”

According to the hypothesis, there is an association between the quality of the various phases of sleep and Alzheimer's disease. This means that the deterioration in the quality of sleep can be a marker of the onset of this disease. There is also evidence that sleep disturbances may play a role in the development of Alzheimer's disease.

The study showed that for each person there is a golden mean. That is, a certain amount of sleep contributes to the normal functioning of the brain. Among the participants, a pattern was revealed: cognitive impairment was seen in people sleeping less than 4,5 hours or more than 6,5 hours per night.

At the same time, the duration of sleep recorded by the encephalogram is one hour shorter than the time recorded by the patients themselves.

In the elderly, prolonged sleep was a sign of poor sleep quality. Lucy says everyone should give themselves enough sleep. For many people it is 7-8 hours.

The researchers stressed that sleep impairments have worsened during the pandemic. According to scientists, if you often wake up in the middle of the night from lack of air or feel tired during the day, this is a sign of one of the sleep disorders. They are currently treatable and diagnosed during a visit to a specialist.